During the past fifty years, the electronics and computing industries have steadily and rapidly advanced the speed of digital computing devices. Semiconductor circuits and metal-conductor-based circuits have played a large role in electronic device technologies. However, semiconductors and metal-conductor-based circuits limit the rate at which electric current can be transmitted between computing devices. For example, manufacturers and designers typically employ copper or aluminum wires to transmit data in the form of electric current or voltage signals. However, the speed limit at which electric current flows through a copper or aluminum wire is about one-tenth of the speed of light. The speed at which copper and aluminum wires transmit electric current limits the rate at which data can be exchanged between computing devices.
Digitized beams of light, such as visible light and infrared (“IR”) light, represent an alternative digital signal information transmitting medium. Unlike electric-current-based signals, light signals can be transmitted at speeds approaching the speed of light. As a result, light-based computing devices may conceivably be faster than electric-current-or-voltage-based computing devices. For example, light-based computing devices that use light signals to transmit digital information may perform operations at about 10 or more times faster than electric-current-based computing devices.
In general, light-based computing devices use optical fibers to transmit digitized light signals. Optical fibers are typically composed of a thin glass or silicon center, referred to as the “core,” that transmits light signals, and a glass or silicon outer layer having a higher refractive index surrounding the core, referred to as the “cladding layer.” The cladding layer reflects light that escapes the core back into the core. An optical fiber that transmits light having a single frequency may have a core diameter that ranges from about 7 microns to about 60 microns, and an optical fiber that transmits light having multiple different frequencies may have a core diameter that ranges from about 60 microns to about 70 microns.
It is often the case that a single optical fiber is used to transmit light signals that are destined for two or more different devices. For example, it may be necessary to transmit a first light signal through an optical fiber to a first device and transmit a second light signal through the same optical fiber to a second device. Typically, manufacturers and designers employ an electric-current-or-voltage-based optical switch to transmit light signals transmitted by a first optical fiber to one or more different optical fibers. In general, electric-current-based-optical switches are composed of an optical receiver and one or more transmitters. The optical receiver accepts an incoming light signal from a first optical fiber, encodes the light signal into an electric-current-or-voltage-based signal which is, in turn, transmitted to one or more of the transmitters. The optical receiver may use a photocell or photodiode to detect the light signal transmitted by the first optical fiber. A transmitter receiving the electric-current-or-voltage-based signal directs an optical device to transmit a light signal to a second optical fiber by turning a light source “on” and “off” in a sequence that regenerates the original light signal. Unfortunately, employing an electric-current-or-voltage-based optical switch to transmit a light signal from a first optical fiber to a second optical fiber delays the light-based-signal-transmission time. Manufacturers, designers, and users of optical based computing devices have recognized the need for faster optical switching devices.